fix: resolve correct aspect name per entity type in UpdateDescription

[cjimti]

Closes #85.

Problem

UpdateDescription() hardcoded editableDatasetProperties as the aspect name (line 59) and readEditableProperties() used the same hardcoded value (line 67). This caused DataHub to reject writes for any non-dataset entity — dashboards, glossary terms, domains, data products, containers, charts, data flows, and data jobs all failed.

This blocked apply_knowledge in mcp-data-platform from updating descriptions on non-dataset entities.

Solution

Introduced a mapping table (descriptionAspectMap) that resolves the correct aspect name and field name for each entity type extracted from the URN:

Entity Type	Aspect Name	Field
dataset	editableDatasetProperties	description
dashboard	editableDashboardProperties	description
chart	editableChartProperties	description
dataFlow	editableDataFlowProperties	description
dataJob	editableDataJobProperties	description
container	editableContainerProperties	description
dataProduct	dataProductProperties	description
domain	domainProperties	description
glossaryTerm	glossaryTermInfo	definition
glossaryNode	glossaryNodeInfo	definition

Special cases handled

• glossaryTerm / glossaryNode: The description field is definition, not description — the mapping resolves this automatically.
• dataProduct / domain: These use non-editable property aspects (no editable prefix).
• Unsupported types (e.g., tag): Return a clear ErrUnsupportedEntityType sentinel error.

Key design decision

Changed editablePropertiesAspect from a fixed struct to a map[string]json.RawMessage wrapper. This preserves all existing fields during read-modify-write regardless of which aspect is being updated — critical because different aspects have different schemas (e.g., glossaryTermInfo has termSource, name, sourceRef, etc. alongside definition).

Changes

pkg/client/write.go

• Added descriptionAspectInfo struct and descriptionAspectMap (10 entity types)
• Added ErrUnsupportedEntityType sentinel error
• Added lookupDescriptionAspect() resolver function
• Replaced fixed editablePropertiesAspect struct with map-based implementation + MarshalJSON() and setDescription() methods
• UpdateDescription() now resolves aspect/field via lookupDescriptionAspect()
• readEditableProperties() now accepts aspectName parameter

pkg/client/write_test.go

• Updated 4 existing tests to work with map-based aspect (no behavior change for datasets)
• Added TestLookupDescriptionAspect — 12 cases covering all 10 supported types + 2 unsupported
• Added TestUpdateDescription_EntityTypes — 5 entity types verify correct aspect name, entity type, and field name in the wire format
• Added TestUpdateDescription_UnsupportedEntityType — verifies ErrUnsupportedEntityType sentinel
• Added TestUpdateDescription_GlossaryTermPreservesExistingFields — verifies definition field is used and sibling fields (termSource, name) are preserved through read-modify-write

Verification

make verify   # All checks passed

• Lint: 0 issues (43 linters)
• Tests: all pass with -race -shuffle=on
• Coverage: above 80% threshold
• Security: gosec + govulncheck clean
• Mutation: above 60% threshold
• Deadcode: only expected library API warnings
• Build: clean

[codecov]

Codecov Report

❌ Patch coverage is 82.14286% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.30%. Comparing base (575023b) to head (4ec89a0).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #86      +/-   ##
==========================================
- Coverage   89.36%   89.30%   -0.06%     
==========================================
  Files          47       47              
  Lines        3290     3309      +19     
==========================================
+ Hits         2940     2955      +15     
- Misses        226      228       +2     
- Partials      124      126       +2     

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.